From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id C1EBAC48297 for ; Mon, 12 Feb 2024 13:27:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 320956B0085; Mon, 12 Feb 2024 08:27:10 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 2A8566B0087; Mon, 12 Feb 2024 08:27:10 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 122766B0088; Mon, 12 Feb 2024 08:27:10 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id F0D466B0085 for ; Mon, 12 Feb 2024 08:27:09 -0500 (EST) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id B1608160A45 for ; Mon, 12 Feb 2024 13:27:09 +0000 (UTC) X-FDA: 81783227778.07.E830C7C Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf29.hostedemail.com (Postfix) with ESMTP id DC6EF120002 for ; Mon, 12 Feb 2024 13:27:07 +0000 (UTC) Authentication-Results: imf29.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf29.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1707744428; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9JD1TXGqGWD1UNXptTZt6Lg9c3qNeGTrBXcQ6eQ8IXg=; b=oazCCr6yoOqwd2e+wqlqAsFwnYTkSBRBLnhmWAJBMt+m+N0M0rklmsrvbAYUTMHalJZaVi LGcfXzZa3CUjMzv2CWa+66R3KqdbVx3YszDwQv1hffUPsqtoQ+LWv2NUon5GzB3PrWE+Nt NrdCibfQiVyIy/l2GXgRIuhMYT3bPI0= ARC-Authentication-Results: i=1; imf29.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf29.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1707744428; a=rsa-sha256; cv=none; b=TjDQIliXK1zFulrNyPRTpqUZGFX44Ls6sNn0i/qNF+IaR1vOszXODG3GOVcMuG8APDMzyx uH4vlzUa/FI5HTC58gTejYozoFlOTkk4Q656rxLJuWC9pPZTHkDsdyvJ9lJPgZS77uiCDW Ojix+frOKrPM1kVSvwLuR2/li5w83uQ= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A3AF9DA7; Mon, 12 Feb 2024 05:27:47 -0800 (PST) Received: from [10.57.78.115] (unknown [10.57.78.115]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 009623F7BD; Mon, 12 Feb 2024 05:27:01 -0800 (PST) Message-ID: Date: Mon, 12 Feb 2024 13:27:00 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 18/25] arm64/mm: Split __flush_tlb_range() to elide trailing DSB Content-Language: en-GB To: David Hildenbrand , Catalin Marinas , Will Deacon , Ard Biesheuvel , Marc Zyngier , James Morse , Andrey Ryabinin , Andrew Morton , Matthew Wilcox , Mark Rutland , Kefeng Wang , John Hubbard , Zi Yan , Barry Song <21cnbao@gmail.com>, Alistair Popple , Yang Shi , Nicholas Piggin , Christophe Leroy , "Aneesh Kumar K.V" , "Naveen N. Rao" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" Cc: linux-arm-kernel@lists.infradead.org, x86@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20240202080756.1453939-1-ryan.roberts@arm.com> <20240202080756.1453939-19-ryan.roberts@arm.com> <9e1d793a-02c9-4dbb-a6d4-1e1c0c42638c@redhat.com> <1ef4c737-0926-424c-9698-794c23370b74@arm.com> <608feac1-8cd6-48c2-87ab-688fb9c0bda4@redhat.com> From: Ryan Roberts In-Reply-To: <608feac1-8cd6-48c2-87ab-688fb9c0bda4@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: DC6EF120002 X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: trhewf617bde1xzmtpypw9n4jpcfidik X-HE-Tag: 1707744427-135915 X-HE-Meta: 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 RkPqRwsC rxKRcwPNPEE+HKR8zr0cUximn2Llpdh8xAXEIip+yOebJtSysA88wEwP85/hs9bTbk+TTuHvnUClI7IgiubUo/H4zXHkcGhI26d+ML7Ws/pLRfFny4ZeHoYOgU3AcozaM+/FN96ccCcclDHPyMEwxnDe6fzAMjcbZl4eg51uKBUM1HnQk/koO3/G+0ydHe2MoP9l+Sph39dCMj+XAUGE2wFxr7rI026XDD+qU5cash6Iugn8UWUiJjOydZWd3KbHu02bI7JJzmNa7OzlBXB6K+jowwFTvyLcTmK8L7nADCJZk2gFIFLmkQs4x47IdeC9XK6a6RagdLKiBu4gnKQKrNBx2UMSCPCOEUJST X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 12/02/2024 13:15, David Hildenbrand wrote: > On 12.02.24 14:05, Ryan Roberts wrote: >> On 12/02/2024 12:44, David Hildenbrand wrote: >>> On 02.02.24 09:07, Ryan Roberts wrote: >>>> Split __flush_tlb_range() into __flush_tlb_range_nosync() + >>>> __flush_tlb_range(), in the same way as the existing flush_tlb_page() >>>> arrangement. This allows calling __flush_tlb_range_nosync() to elide the >>>> trailing DSB. Forthcoming "contpte" code will take advantage of this >>>> when clearing the young bit from a contiguous range of ptes. >>>> >>>> Tested-by: John Hubbard >>>> Signed-off-by: Ryan Roberts >>>> --- >>>>    arch/arm64/include/asm/tlbflush.h | 13 +++++++++++-- >>>>    1 file changed, 11 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/arch/arm64/include/asm/tlbflush.h >>>> b/arch/arm64/include/asm/tlbflush.h >>>> index 79e932a1bdf8..50a765917327 100644 >>>> --- a/arch/arm64/include/asm/tlbflush.h >>>> +++ b/arch/arm64/include/asm/tlbflush.h >>>> @@ -422,7 +422,7 @@ do {                                    \ >>>>    #define __flush_s2_tlb_range_op(op, start, pages, stride, tlb_level) \ >>>>        __flush_tlb_range_op(op, start, pages, stride, 0, tlb_level, false, >>>> kvm_lpa2_is_enabled()); >>>>    -static inline void __flush_tlb_range(struct vm_area_struct *vma, >>>> +static inline void __flush_tlb_range_nosync(struct vm_area_struct *vma, >>>>                         unsigned long start, unsigned long end, >>>>                         unsigned long stride, bool last_level, >>>>                         int tlb_level) >>>> @@ -456,10 +456,19 @@ static inline void __flush_tlb_range(struct >>>> vm_area_struct *vma, >>>>            __flush_tlb_range_op(vae1is, start, pages, stride, asid, >>>>                         tlb_level, true, lpa2_is_enabled()); >>>>    -    dsb(ish); >>>>        mmu_notifier_arch_invalidate_secondary_tlbs(vma->vm_mm, start, end); >>>>    } >>>>    +static inline void __flush_tlb_range(struct vm_area_struct *vma, >>>> +                     unsigned long start, unsigned long end, >>>> +                     unsigned long stride, bool last_level, >>>> +                     int tlb_level) >>>> +{ >>>> +    __flush_tlb_range_nosync(vma, start, end, stride, >>>> +                 last_level, tlb_level); >>>> +    dsb(ish); >>>> +} >>>> + >>>>    static inline void flush_tlb_range(struct vm_area_struct *vma, >>>>                       unsigned long start, unsigned long end) >>>>    { >>> >>> You're now calling dsb() after mmu_notifier_arch_invalidate_secondary_tlbs(). >>> >>> >>> In flush_tlb_mm(), we have the order >>> >>>      dsb(ish); >>>      mmu_notifier_arch_invalidate_secondary_tlbs() >>> >>> In flush_tlb_page(), we have the effective order: >>> >>>      mmu_notifier_arch_invalidate_secondary_tlbs() >>>      dsb(ish); >>> >>> In flush_tlb_range(), we used to have the order: >>> >>>      dsb(ish); >>>      mmu_notifier_arch_invalidate_secondary_tlbs(); >>> >>> >>> So I *suspect* having that DSB before >>> mmu_notifier_arch_invalidate_secondary_tlbs() is fine. Hopefully, nothing in >>> there relies on that placement. >> >> Will spotted this against v3. My argument was that I was following the existing >> pattern in flush_tlb_page(). Apparently that is not correct and needs changing, >> but the conclusion was to leave my change as is for now, since it is consistent >> and change them at a later date together. > > Good, I think you should add a few words to the patch description ("ordering > might be incorrect, but is in-line with __flush_tlb_page()"; will be resolved > separately). > ACK, will do. Thanks!